1. Field of the Invention
The subject invention relates to transducing methods and transducers and, more specifically, to transducers of the type having a mass oscillating in the manner of a piston in a cylinder, and to methods for operating such transducers, as well as to systems for adjusting the damping of transducers.
2. Disclosure Statement
This disclosure statement is made pursuant to the duty of disclosure imposed by law and formulated in 37 CFR 1.56(a). No representation is hereby made that information thus disclosed in fact constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends on uncertain and inevitably subjective elements of substantial likelihood and reasonableness, and inasmuch as a growing attitude appears to require citation of material which might lead to a discovery of pertinent material.
Transducer systems pertinent to this disclosure statement are apparent from U.S. Pat. No. 4,110,731 for Vibration Transducer With Improved Viscous Damping, by Ebbert Lee Elswood, issued Aug. 29, 1978 to the subject assignee, and herewith incorporated by reference herein, and from the art of record or otherwise cited in that Elswood patent and also incorporated by reference herein.
In the course of a novelty search, four patents were noted, comprising U.S. Pat. No. 2,615,940, by M. Williams, disclosing electrokinetic transducing methods and apparatus having transducer elements located in a conduit or other passage between two fluid chambers, U.S. Pat. No. 2,717,369, by T. Bardeen et al, disclosing a pressure-sensitive deep well seismograph detector, providing free fluid flow by holes in a partition wall located between a pair of fluid chambers and encompassing an electric transducer, U.S. Pat. No. 2,915,738, by C. B. Vogel, which discloses a hydrophone detector providing for fluid leakage around a pressure-sensing diaphragm in reponse to excess pressure, and U.S. Pat. No. 3,662,327, by G. White, which discloses a seismometer wherein pressure transducing elements are disposed in a passage through a seismic mass or in a conduit around the seismic mass located between two fluid chambers.
Among the transducer systems so far mentioned, there persists a need for a generally applicable and efficiently operable damping adjustment system. In this respect, the above mentioned Elswood patent discloses a damping adjustment approach which has worked reasonably well in practice. In particular, Elswood achieved a measure of damping control by building the transducer for the maximum damping required in a given range of applications, and by then calibrating the transducer damping downwardly as required, by a cutting of notches into, or formation of similar peripheral recesses on, a piston ring on the outside of the seismic mass.
While that approach has proved its utility in numerous applications, it does present the drawback of requiring damping adjustments to be done by manual material removing operations, involving typically a repeated assembly, testing and disassembly procedure for damping each unit properly. Also, overadjustment resulted in wastage since a removal of too much material generally could only be undone by replacement of the particular part. Moreover, the careful attention of highly skilled personnel was continuously required throughout the elaborate damping adjustment procedure.